$ D = \left[\begin{array}{rrr}2 & 7 & 1 \\ 4 & 5 & 9\end{array}\right]$ What is $ D^{T}$ ?
To find the transpose, swap the rows and columns. $ D^{T}$ = $\left[\begin{array}{rr}2 & 4 \\ 7 & 5 \\ 1 & 9\end{array}\right]$